1. Detailed Description of the Invention
The present invention relates to an illuminated switch unit, and more particularly to an illuminated switch unit placed side by side on a steering wheel in an automobile, used for setting speed in cruise control and for controlling volume for a radio receiver or the like.
2. Description of the Prior Art
In recent years, the electronization of automobiles has advanced, and various controls brought about by the electronization are constructed such that various functions placed side by side on an automotive steering wheel can be performed by various switches. This steering wheel is, as shown in FIG. 5, provided with: a center pad 20 in which, for example, an air bag of the air bag system is housed; an illuminated switch unit section 21; a supporting section 24 for supporting the illuminated switch unit section 21; and a steering wheel 29 supported by the illuminated switch unit section 21 and the supporting section 24.
This illuminated switch unit section 21 has a first illuminated switch unit section 22 for switching, for example, the cruise control (speed control mechanism) to ON or OFF or the like and a second illuminated switch unit section 23 for switching, for example, between a radio receiver and an automotive telephone.
The first illuminated switch unit section 22 is provided with: a first illuminated rocking switch unit 25 having a first rocking knob 25a of a rocking and depression type; and a first illuminated switch unit 26 having a plurality of (for example, two) first push-button sections 26a of a vertical depression type.
The structure is arranged such that by means of these two first push-button sections 26a, for example, the cruise control is turned ON or OFF, and speed set in the cruise control is ascertained and controlled, and that by means of the first rocking knob 25a, speed to be set is adjusted (speed-up or slowdown).
The second illuminated switch unit section 23 is provided with: a second illuminated rocking switch unit 27 having a second rocking knob 27a of the rocking and depression type; and a second illuminated switch unit 28 having a plurality of (for example, four) second push-button sections 28a of the vertical depression type.
The structure is arranged such that by means of these four second push-button sections 28a, for example, switching between the radio receiver and the automotive telephone, and increase or decrease in a receive frequency to adjust the receive frequency of the radio receiver are performed, and that by means of the second rocking knob 27a, for example, the volume of the radio receiver is increased or decreased.
Next, with reference to the drawings, a detailed description will be made of the above-described conventional first illuminated rocking switch unit.
FIG. 6 is an exploded perspective view showing a conventional illuminated rocking switch unit section; FIG. 7 is a partial perspective view showing a conventional case for the illuminated rocking switch unit; FIG. 8 is an exploded perspective showing a conventional movable contact, elastic member, printed circuit board, and light source of the illuminated rocking switch unit; and FIG. 9 is a partial sectional view for explaining the conventional illuminated rocking switch unit.
As shown in FIGS. 6 to 9, the conventional case 1 of the first illuminated rocking switch unit is made of synthetic resin material such as phenol resin and epoxy resin, is obtained by fabrication, and has: a top wall 1a; and a substantially rectangular recess 1d provided on the top wall 1a at a predetermined position, having openings 1b and 1c (see FIG. 7) in an up-and-down direction. Also, the recess 1d is provided with: side walls 1i and 1j for surrounding on all sides; bottom walls 1e for surrounding all around an opening 1c at the lower part; a pair of holes 1g provided in the bottom walls 1e; and a pair of cylindrical column-shaped protrusions 1h provided above the respective holes 1g. Each of the protrusions 1h protrudes from the side wall 1i of the recess 1d toward the inside (toward the substantially central portion of the recess 1d).
The pair of holes 1g have structure to be necessarily formed from the structure of a forming mold for forming the case 1 in order to form the pair of protrusions 1h within the recess 1d, and is formed for so-called rapping.
This case 1 is the same as the case for the illuminated switch unit section 21 shown in FIG. 5, is provided side by side on, for example, an automotive steering wheel 29, and is made integral with a center pad 20 each other in such a manner that the case 1 is rotated together with the rotation of the steering wheel 29.
As shown in FIG. 6, a rocking knob 2 as a movable knob is a substantially box-shaped one, made of synthetic resin material such as phenol resin and epoxy resin, and obtained by fabrication, and has a substantially rectangular top surface 2c; sides 2d extendedly provided from the outer periphery of the top surface 2c downward, for surrounding on all sides; a pair of circular holes 2e provided on the first opposed sides 2d; and a pair of drive sections (not shown) protruding from the rear surface side of the top surface 2c outwardly. This top surface 2c is formed with a first depression section 2a and a second depression section 2b. The pair of drive sections (not shown) protrude from the rear surface sides of the first depression section 2a and the second depression section 2b outwardly (toward the inside of the substantially box-like shape) respectively.
On the surfaces of the first depression section 2a and the second depression section 2b, picture symbol indicating sections 2g such as+(plus) and-(minus) symbols are formed translucently, or using synthetic resin material (such as so-called two-color fabrication) through which light is transmitted (transparent) The picture symbol indicating sections 2g such as these+(plus) and-(minus) symbols are constructed so as to be brightly indicated by illumination from a light source 6 to be described later.
This rocking knob 2 is disposed within the recess 1d of the case 1, and the protrusions 1h of the case 1 are inserted into the holes 2e in the rocking knob 2 so that the rocking knob 2 is rockably supported and disposed. In this state, the first depression section 2a or the second depression section 2b of the top surface 2c is depressed, whereby the rocking knob 2 is rocked to thereby move the drive section (not shown) in an up-and-down direction.
Also, in this state, the lower end surface of the side 2d of the rocking knob 2 and the hole 1g in the case 1 are disposed to oppose to each other, and there is formed a slight gap 11 (see FIG. 9) between the side 2d and the side wall 1i.
A slider 3 is made of synthetic resin material such as phenol resin and epoxy resin, is obtained by fabrication, and is provided with a substantially box-shaped body section 3a and a pair of drive sections 3b protruding from the body section 3a outwardly. This slider 3 is mounted to the case 1 by appropriate means in a state in which each body section 3a abuts upon each drive section (not shown) of the rocking knob 2.
In each of the sliders 3, the rocking of the rocking knob 2 depresses the body section 3a to thereby drive each drive section 3b in a direction indicated by an arrow B (see FIG. 6).
There are provided a plurality of (for example, four) movable contacts 4. Each of the movable contacts 4 is made of elastic material such as rubber, is obtained by fabrication, and has: a cylindrical column-shaped movable section 4a; a contact section 4b provided on the under surface of the movable section 4a; and a substantially dome-shaped supporting section 4c for outwardly protruding from the outer periphery of the lower end of the movable section 4a. This movable contact 4 is disposed within the opening 1c in the case 1, and in this state, the movable section 4a is disposed to oppose to and abut upon the drive section 3b of the slider 3.
As regards the movable contact 4, the movement of the drive section (not shown) of the rocking knob 2 in a direction indicated by the arrow B presses the drive section (not shown) against the slider 3, and the contact section 4b of the movable contact 4 is driven in the direction indicated by the arrow B (see FIG. 6) through the slider 3. Concerning the movable contact 4, two groups (four in total) are formed in groups of, for example, two.
An elastic member 7 is made of transparent or translucent elastic material such as rubber, is obtained by fabricating into a substantially flat plate shape, and is provided with a housing section 7a having a plurality of (for example, two) substantially rectangular/box-shaped top walls 7b, for housing a light source 6. The housing section 7a is formed so as to outwardly protrude from the elastic member 7. Also, the top wall 7b is formed of transparent elastic material. This elastic member 7 is integrally formed with the movable contacts 4, and at this time, the housing section 7a is disposed so as to be sandwiched between a group of (two) movable contacts 4.
As shown in FIG. 8, a printed circuit board 5 is made of, for example, flat plate-shaped glass-filled phenol resin material or the like, and on one surface thereof, has: a plurality of groups (for example, four groups) of stationary contacts 5a and 5a in groups of a pair; terminals 5b to which the light source 6 such as a light emitting diode (LED) is connected; and a predetermined circuit pattern (not shown) connected to the stationary contacts 5a and the terminals 5b.
The stationary contacts 5a are provided so as to sandwich the light source 6 between them. The light source 6 is connected to the terminals 5b of the printed circuit board 5, and is connected to a wiring pattern having a predetermined shape not shown on the printed circuit board 5 and is disposed.
This light source 6 is disposed such that it is lighted through current from a power source (not shown), the rocking knob 2 is illuminated from the rear surface side by the lighting to brightly indicate a position where the rocking knob 2 is disposed, and to brightly indicate the picture symbol indicating sections 2g formed on the first depression section 2a and the second depression section 2b. In this manner, the position of the rocking knob 2 can be found even in dark conditions such as nighttime to thereby enable the rocking knob 2 to be easily operated.
The elastic member 7 is bonded onto the printed circuit board 5, in this state, the light source 6 thereof is housed within the housing section 7a of the elastic member 7, and the pair of stationary contacts 5a are disposed to oppose to the contact section 4b of the movable contact 4. In other words, the movable contact 4 is brought into and out of contact with the stationary contact 5a to thereby form the switch.
The elastic member 7 bonded onto the printed circuit board 5 is disposed together with the printed circuit board 5 within the case 1, and in this state, the holes 1g in the case 1 are disposed in a state in which they are penetrated, and therefore, are opened.
A holding substrate 8 is made of synthetic resin material such as phenol resin and epoxy resin, is obtained by fabricating into a substantially flat plate shape, has a plurality of (for example, four) holes 8a formed on the outer edge section thereof and has, on one surface, a plurality of cylindrical column-shaped struts (not shown). On this holding substrate 8, the printed circuit board 5 is restrained by the strut (not shown) and is held on the holding substrate 8.
This holding substrate 8, by which the printed circuit board 5 and the elastic member 7 are held, is disposed within the case 1 from the direction of the opening 1c in the case 1, and the case 1 and the holding substrate 8 are made integral with each other by means of screws 9 or the like in a state in which the screws 9 or the like are inserted into holes 8a in the holding substrate 8. By making them integral, an illuminated rocking switch unit is formed.
Next, a description will be made of an operation of the illuminated rocking switch unit.
In this illuminated rocking switch unit, when the first depression section 2a or the second depression section 2b of the rocking knob 2 is depressed downward, the drive section (not shown) of the rocking knob 2 depresses a movable section 4a of the movable contact 4 downward (direction indicated by an arrow B in FIG. 6) through a drive section 3b of the slider 3. When the movable section 4a is depressed downward, contact sections 4b provided on the under surface of the movable section 4a are caused to abut upon a pair of stationary contacts 5a and 5a of the printed circuit board 5. This abutting upon the stationary contacts 5a and 5a brings the pair of stationary contacts 5a and 5a into conduction through the contact section 4b to cause the illuminated rocking switch unit to be in an ON-state.
This illuminated rocking switch unit is constructed such that the light source 6 for the illuminated rocking switch unit lights the moment automotive headlights (not shown) are lighted, and light from the light source 6 illuminates the rear surface side of the first depression section 2a and the second depression section 2b of the rocking knob 2 so that the picture symbol indicating sections 2g on the first depression section 2a and the second depression section 2b is made bright.
In the conventional illuminated rocking switch unit, however, light from the light source 6, which illuminates the picture symbol indicating section 2g of the rocking knob 2 (movable knob) from the rear surface side, passes through the top wall 7b of the housing section 7a in the elastic member 7 to illuminate the first depression section 2a and the second depression section 2b of the rocking knob 2 from the rear surface side. At this time, there is a problem that the light from the light source 6 passes through the hole 1g in the case 1, and the light further leaks outwardly of the illuminated rocking switch unit through a gap 11 formed between the side wall 1i of the case 1 and the side 2d of the rocking knob 2. Also, there is a problem that the light from the gap 11 becomes direct light for the automotive driver and the light may dazzle him or her.